Abstract: In recent years, avirtual human motion modeling has been a hot research topic in computer graphics．Inverse kinematics is a key technology for motion modeling．A novel inverse kinematics algorithm based on the human constrained joints for rea-l time human motion modeling is proposed．We improve the traditional cyclic coordinate descent （CCD） algorithm based on bone distance to make the motion more fluent and natural．Then, awe incorporate SHAKE algorithm, awhich is normally used in biological molecules motion simulation with the CCD algorithm for short-distance motion modeling． Furthermore, awe develop an analytic algorithm accounting for the concurrent the motion of multiple nodes, ato facilitate the simulation of human motion effected by mult-i joints．The result of our algorithm is very close to those generated with motion capture data, awhich indicates the application potential of our algorithm．